Band spring shaped to be arranged straddling a brake disc

Abstract

The present invention relates to a band spring (1) shaped to be arranged straddling a brake disc (2), wherein said band spring (1) is adapted to apply an elastic action to a first brake pad (3) to bias said first brake pad (3) away from said brake disc (2), and to bias said first brake pad (3) in the radial direction (R-R); said band spring (1) is adapted to apply an elastic action to a second brake pad (4) to bias said second brake pad (4) in the radial direction (R-R); - said band spring (1) comprises a ribbon-shaped spring body (5); said spring body (5) comprises an action body portion (6) adapted to bias said first brake pad (3) and a reaction body portion (7) adapted to abut against said second brake pad (4); said spring body (5) has a centerline (9); said spring body (5) has an asymmetric shape with respect to said centerline (9); said spring body (5) comprises a fixing portion (10) to fix said band spring (1) to a caliper body (11), placed in said action body portion (6) away from said centerline (9).

Description

"Band spring shaped to be arranged straddling a brake disc"DESCRIPTION

[0001] . Field of the invention

[0002] . The present invention relates to a band spring for a braking device of a disc brake, as well as to a brake caliper comprising a caliper body, brake pads and a band spring, as well as to a brake caliper comprising said brake caliper and a brake disc .

[0003] . Background art

[0004] . In a disc brake , the brake caliper is generally arranged straddling the external peripheral margin of a brake disc, adapted to rotate about a rotation axis (X-X) defining an axial direction (A-A) . In a brake disc, there are also defined a radial direction (R-R) substantially orthogonal to said axial direction (A-A) , a circumferential direction (C-C) orthogonal to both said axial direction (A-A) and said radial direction (R-R) , and a tangential direction ( T-T ) locally, or rather punctually, i . e . , in an intersection point of an axial and a radial direction, orthogonal to both said axial direction (A-A) and said a radial direction (R-R) .

[0005] . As is known, discs for a disc brake comprise a bell or support adapted to associate the disc with a hub or wheel axle of a vehicle , from which an annular portion extends , referred to as a braking band, intended to cooperate with the brake pads of a caliper .

[0006] . Disc brake springs are known, consisting of a central portion and two end portions , where the end portions rest againstthe pads so as to stress the pads elastically away from each other to ensure a separation of the pads from the brake disc after each braking action .

[0007] . The known springs are thus used to obtain a three- fold action :

[0008] . - reducing the pad vibration and thus limit the undesired movement of pads (vibration, noise and abnormal wear) ;

[0009] . - moving the pads away from the brake disc to reduce or eliminate a residual braking torque ( residual torque ) due to undesired contacts between the pads and the brake disc, with the brake being deactivated;

[0010] . - obtaining uniform wear of the friction linings of the pads .

[0011] . For example, JP2011226552A shows such a solution .

[0012] . The springs of the prior art usually abut against an apical portion of the pads and thus transmit a direct separation force to the pads at the top of the pads , which top is understood as the radially outer edge with respect to the rotation axis of the brake disc .

[0013] . In braking systems of the prior art, the correct positioning between the disc brake components , in particular between the spring and the brake pads , is entrusted to the friction forces which are generated by virtue of the elastic force , generally decomposable along the three spatial directions , applied by the spring upon its deformation on the support , i . e . , the pad plate .

[0014] . The value of these frictional forces depends on :

[0015] . the materials in contact which define the friction coef ficient ;

[0016] . - the value of the exchanged elastic force of the spring .

[0017] . I f the system is subj ected to external forces , e . g . , vibrations or involuntary contact with an external agent or during maintenance of the caliper or a general force outside the system, the latter decomposes along the two main directions which are parallel and perpendicular to the geometry in the contact zone .

[0018] . The balance between the spring and the pad remains as such if the friction forces developed, by virtue of the contact forces , are greater than the sliding forces of the spring on the pad .

[0019] . Otherwise , the system is perturbed, taking itself to a new balance position di fferent from the first one, which changes the dynamics of the exchanged forces resulting in an impact on the functionality of the spring-pad assembly, altering the correct functionality of the braking system .

[0020] . In particular, in brake calipers for motorcycles and even more in particular in brake calipers of the floating type, springs are used that involve the application of a radial load to the pads with the aim of limiting the undesired movement of pads (vibrations , noise and abnormal wear ) . The prior art for the floating calipers involves the use of " flat, " or band-shaped, pad springs with fins j oined by a crosspiece . The fins work on the pad from the reaction side and the action side (or piston side ) , respectively, and are usually connected to each other . These known solutions are not adapted to obtain a suitable axial thrust component for moving thebrake pads away from the braking surfaces of the brake disc .

[0021] . In order to solve this problem, in the prior art a wire spring is added in parallel with the band spring, which wire spring has the task to generate an elastic bias in the axial direction, . However, this solution is obviously complex and expensive to implement , obliging the use of two di fferent springs in the same brake caliper .

[0022] . Therefore , a need is strongly felt to bias the movement of the brake pad, so as to generate a precise axial load as constant as possible throughout the life of the brake pads , thus during the wear of the brake pad friction material .

[0023] . In particular, the need is still strongly felt to ensure that the position of the spring-pad contact point does not change even following the external biases applied to the system.

[0024] . Solut ion

[0025] . It is an obj ect of the present invention to provide a band spring with the ability to ensure an axial action for the pads to move away from the surfaces of the brake disc when the braking action ceases , as well as in which the elastic action is as homogeneous as possible during wear of the brake pads .

[0026] . These and other obj ects and advantages are achieved by a band spring according to claim 1 .

[0027] . Some advantageous embodiments are the subj ect of the dependent claims .

[0028] . By virtue of the suggested solutions , it is possible to provide a band spring and thus a brake caliper and a disc brakewhich ensure an axial elastic bias to the pads to allow them to move away from the surfaces of the brake disc when the braking action ceases .

[0029] . Additionally, the invention allows having an elastic action kept as homogeneous as possible during wear of the brake pads .

[0030] . According to an embodiment, the invention provides an asymmetric spring for floating calipers with reaction-side ( side of the floating caliper without pistons ) and action-side ( side of the floating caliper with at least one piston) arms separated from each other .

[0031] . The reaction-side and action-side arms are deformed during the pad assembly, ensuring the radial load component, but at least one the action-side also the desired axial load component .

[0032] . The band spring is "asymmetric" because it is not symmetric with respect to a circumferential direction passing through the center of the spring : the windows or "cuts" which divide the reaction-side and action-side arms are displaced with respect to the central flap of the spring, indeed the action-side arms are longer than the reaction-side arms in the axial direction .

[0033] . The action-side arms are those responsible for generating the axial load during the braking action . Indeed, in operation, due to the action of the action-side pad, the action-side arms flex radially, twisting the central spring segment ( torsional spring function) and ultimately generating the required axial component .

[0034] . The technical effect resulting from the suggested springgeometry is the maximization of the lever arm which generates the axial load .

[0035] . Moreover, since the action-side , or piston-side, pad translates axially during its service li fe due to wear of the friction material , the geometry of the action-side arms ensures the generation of the axial component independently of the axial advancement of the pad due to wear .

[0036] . Additionally, according to an embodiment, a decoupling of the reaction-side and action-side, or piston-side, arms occurs , accommodating any load imbalances due to faults in the manufacturing or placement of the brake pads .

[0037] . The band spring according to the invention further comprises two retaining teeth in the reaction-side arms , obtained by folding the end of the arms .

[0038] . The resulting technical effect is to limit the axial movement of the reaction-side pad, during both installation on the vehicle and use . Indeed, the reaction-side pad always remains stationary with respect to the caliper body and abutting against these reaction teeth, also referred to as third retaining teeth below .

[0039] . The spring according to the invention further comprises a fastening region for fastening the caliper body, or fixing portion, not centrally positioned with respect to the band spring, but displaced in the body action portion of the spring which, according to an embodiment, is provided at a first fixing end of a central spring segment , which segment is mechanically independent ascompared to the action and reaction arms of the spring .

[0040] . The technical effect is to provide that , during operation, the fastening or fixing zone is not further biased by loads other than those due only to the assembly of the band spring to the caliper body . Indeed, the loads generated in the spring during the braking action tend to be localized in the central segment of the spring, without further overloading the fixing portion of the spring .

[0041] . Figures

[0042] . Further features and advantages of the band spring will become apparent from the description provided below of preferred exemplary embodiments thereof , given by way of non-limiting indication, with reference to the accompanying drawings , in which :

[0043] . - figure 1 depicts an axonometric view of a brake caliper of the floating type viewed from the action-side, preferably but not necessarily, a brake caliper for motorcycles ; this brake caliper is placed straddling a brake disc shown here with dotted lines , and together with the brake disc it forms a disc brake ;

[0044] . - figure 2 shows an axonometric view, sectioned according to a plane comprising the radial and circumferential directions , of the caliper in figure 1 , sectioned at the centerline of the plate of the reaction pad;

[0045] . - figure 3 depicts a section view according to a plane comprising the axial and radial directions of the caliper in figure 1 , sectioned at the symmetry axis of the thrusting means ;

[0046] . figure 4 depicts an axonometric view of the brakecaliper in figure 1 viewed from the reaction side;

[0047] . - figure 5 shows an axonometric view, sectioned according to a plane containing the radial and circumferential directions, of the caliper in figure 4, in which the section is made facing the first brake pad, or action pad;

[0048] . - figure 6 depicts an axonometric view of the caliper in figure 4 in which the floating body of the brake caliper is depicted shifted radially to show the bracket, the guides, the brake pads, and the band spring;

[0049] . - figure 7 shows an axonometric view, viewed from the circumferential and action side, of the first and second brake pad assembly and the associated band spring;

[0050] . - figure 8 depicts an axonometric view of the assembly in figure 7 but from the opposite side in the circumferential direction;

[0051] . - figure 9 shows an axonometric view of a band spring from the radial side where the fixing arms project;

[0052] . - figure 10 depicts an axonometric view of the band spring in figure 9 but from the opposite radial side;

[0053] . - figure 11 shows a plan view, i.e., according to the inner radial course of the radial direction, of the band spring in figure 9;

[0054] . - figure 12 depicts a side view, i.e., in a direction tangential to the circumferential direction, of the band spring in figure 9;

[0055] . - figure 13 shows an axial side view, i.e., in the axialdirection, of the band spring in figure 9 ;

[0056] . - figures 14 and 15 depict plan views , in which the pads are shown with only the support plates thereof , of the assembly in figure 7 with the pads in unworn condition and in completely worn condition .

[0057] . Description of some preferred embodiments

[0058] . According to a general embodiment, a band spring 1 shaped to be arranged straddling a brake disc 2 is provided .

[0059] . Said brake disc 2 is adapted to rotate about a rotation axis X-X which defines an axial direction A-A parallel to said rotation axis XX, a radial direction R-R orthogonal to said rotation axis X-X, and a circumferential direction C-C orthogonal to both said axial direction A-A and said radial direction R-R . Moreover, a tangential direction T-T which is locally, or rather punctually, i . e . , in an intersection point of an axial A-A and a radial R-R direction, is defined to be orthogonal to both said axial direction A-A and said radial direction R-R .

[0060] . Said radial direction R-R has an outer radial course Re, when directed away from said rotation axis X-X, and an inner radial course Ri , when directed toward said rotation axis X-X .

[0061] . Said band spring 1 , when assembled in a caliper body 11 which accommodates opposite first and second brake pads 3 , 4 , applies an elastic action to said first brake pad 3 , or action pad, to bias said first brake pad 3 away from said brake disc 2 , thus substantially in the axial direction A-A, and to bias said first brake pad 3 in the radial direction R-R .

[0062] . Moreover, said band spring 1, when assembled in a caliper body 11 which accommodates opposite first and second brake pads 3, 4, applies an elastic action to said second brake pad 4, or reaction pad, opposed to said first brake pad or action pad 3, to bias said second brake pad 4 in the radial direction R-R.

[0063] . Said band spring 1 comprises a spring body 5.

[0064] . Said spring body 5 is ribbon-shaped. For example, it consists of a band. For example, said spring body 5 is obtained by cutting a sheet of spring material, e.g., spring steel, and shaping said cut piece into a three-dimensional template as specified below.

[0065] . Said spring body 5 comprises an action body portion 6 adapted to bias said first brake pad 3.

[0066] . Said spring body 5 comprises a reaction body portion 7 adapted to abut against said second brake pad 4.

[0067] . Said spring body 5 has a centerline 9 parallel to the circumferential direction C-C. For example, said centerline 9, when the spring is assembled straddling the brake disc 2, is a direction T-T tangent to said circumferential direction C-C and extending transversely to said axial direction A-A and is placed in the middle of said spring body 5, the extension of which is evaluated in the axial direction A-A.

[0068] . Said spring 5 has an asymmetric shape, i.e., not symmetric, with respect to said centerline 9.

[0069] . Said spring body 5 comprises a fixing portion 10 to fix said band spring 1 to a caliper body 11.

[0070] . As mentioned above, said caliper body 11 is placedstraddling said brake disc 2 and accommodates said first and second pads 3 , 4 .

[0071] . Said fixing portion 10 is placed in said action body portion 6 away from said centerline 9 .

[0072] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner .

[0073] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner, each with at least one action segment 14 , 15 extending in the axial direction A-A.

[0074] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner each forming an "L"-shape having at least one action segment 14 , 15 extending in the axial direction A-A.

[0075] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner, each with at least one action segment 14 , 15 extending in the axial direction A-A. Said action segments 14 , 15 being arranged parallel to each other .

[0076] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 which, when the bandspring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner, each with at least one action segment 14 , 15 having a raised action arm edge 16 . By virtue of the provision of this feature , it is possible to provide a lower resting surface, i . e . , facing the brake pad, which is rounded, thus adapted to avoid the band spring 1 from snagging against said first brake pad 3 in the circumferential direction C-C .

[0077] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner .

[0078] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner, each with at least one reaction segment 19 , 20 extending in a direction tangent to said circumferential direction C-C .

[0079] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner each forming an "S"-shape and with at least one reaction segment 19 , 20 extending in a direction tangent to the circumferential direction C-C .

[0080] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in acantilevered manner, each with at least one reaction segment 19 , 20 extending in a direction tangent to said circumferential direction C-C .

[0081] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 which, when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner, each with at least one reaction segment 19 , 20 having a raised reaction arm end edge 21 . By virtue of the provision of this feature, the band spring has a lower surface resting on the brake pad, which is rounded and adapted to avoid the band spring 1 from snagging against said second brake pad 4 , at least in the circumferential direction C-C .

[0082] . According to an alternative embodiment, said two action arms 12 , 13 and said two reaction arms 17 , 18 , when the band spring 1 is disassembled from said caliper body 11 , proj ect in a cantilevered manner separately from one another .

[0083] . According to an alternative embodiment, said two action arms 12 , 13 and said two reaction arms 17 , 18 , when the band spring 1 is disassembled from said caliper body 11 , all four proj ect in a cantilevered manner and separately from one another .

[0084] . According to an alternative embodiment, said action arm action segments 14 , 15 of said two action arms 12 , 13 have greater extension in the axial direction A-A than the extension in the axial direction A-A of said reaction arm reaction segments 19, 20 of said two reaction arms 17 , 18 .

[0085] . According to an alternative embodiment, said action bodyportion 6 comprises two action arms 12 , 13 , where when said band spring 1 is disassembled from said caliper body 11 , said two action arms 12 , 13 are arranged to form each an action surface 22 placed in an inclined plane or action plane, indicated by reference sign Pa, which, in a plane comprising the axial A-A and radial R-R directions , forms an action angle 23 with respect to the axial direction A-A.

[0086] . According to an alternative embodiment, said action body portion 6 comprises two action arms 12 , 13 , where when said band spring 1 is disassembled from the caliper body 11 , said two action arms 12 , 13 are arranged to form each an action surface 22 placed in an inclined plane or action plane Pa which, in a plane comprising the axial A-A and radial R-R directions , forms an action angle 23 with respect to the axial direction A-A.

[0087] . Said action angle 23 is of predetermined magnitude so that , when the band spring 1 is assembled in said caliper body 11 and biases said first brake pad 3 , said two action arms 12 , 13 are arranged to preload in a predetermined manner said first brake pad 3 to bias said first brake pad 3 in a predetermined and substantially approached in the axial direction A-A and away from the brake disc 2 and to bias in a predetermined and substantially approached manner the first brake pad 3 in the inner radial direction Ri .

[0088] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 , where when said band spring 1 is disassembled from the caliper body 11 , said two reaction arms 17 , 18 are arranged to form each a reaction surface 24 placedin an inclined plane or reaction plane Pr which, in a plane comprising the circumferential C-C and radial R-R directions , forms a reaction angle 25 with respect to the direction T-T tangential to the circumferential direction C-C .

[0089] . According to an alternative embodiment, said reaction body portion 7 comprises two reaction arms 17 , 18 , where, when said band spring 1 is disassembled from the caliper body 11 , said two reaction arms 17 , 18 are arranged to form each a reaction surface 24 placed in an inclined plane or reaction plane Pr which, in a plane comprising the circumferential C-C and radial R-R directions forms a reaction angle 25 with respect to a direction T-T tangential to the circumferential direction C-C . Said action angle 25 is of predetermined magnitude so that when the band spring 1 is assembled in said caliper body 11 and biases said second brake pad 4 , said two reaction arms 17 , 18 are arranged to preload in a predetermined manner the second brake pad 4 to bias said second brake pad 4 in a predetermined manner and substantially approached in the inner radial direction Ri .

[0090] . According to an alternative embodiment , said fixing portion 10 comprises two fixing arm 26 , 27 which snap-couple to the caliper body 11 .

[0091] . According to an alternative embodiment , said fixing portion 10 comprises two fixing arms 26 , 27 , which snap-couple to the caliper body 11 , which extend substantially in the radial direction R-R;

[0092] . or where

[0093] . said fixing portion 10 comprises two fixing arms 26 , 27 adapted to snap-couple to the caliper body 11 , each arm having a fixing arm end 28 folded to fit into a fixing seat 29 provided in the caliper body 11 .

[0094] . According to an alternative embodiment, said band spring 1 comprises a central spring segment 30 .

[0095] . According to an alternative embodiment , said fixing portion 10 proj ects from a first fixing end 31 of said central spring segment 30 .

[0096] . According to an alternative embodiment, said action body portion 6 adapted to bias said first brake pad 3 proj ects from an intermediate portion 32 of said central spring segment 30 .

[0097] . According to an alternative embodiment, said reaction body portion 7 adapted to abut against said second brake pad 4 proj ects from a second end 33 of said central spring segment 30 , said end being opposite to said first fixing end 31 .

[0098] . According to an alternative embodiment, said band spring 1 comprises a central spring segment 30 with longitudinal extension directed according to the substantially axial direction A-A, when the band spring 1 is assembled on said caliper body 11 .

[0099] . According to an alternative embodiment , said fixing portion 10 proj ects with two fixing arms 26, 27 from opposite edges of a first fixing end 31 of said central spring stretch 30 .

[0100] . According to an alternative embodiment, said action body portion 6 adapted to bias said first brake pad 3 proj ects with two action arms 12 , 13 from opposite edges of an intermediate portion 32of said central spring segment 30 .

[0101] . According to an alternative embodiment, said reaction body portion 7 adapted to abut against said second brake pad 4 proj ects with two reaction arms 17 , 18 from opposite edges of a second end 33 of said central spring segment 30 , said end being opposite to said first fixing end 31 .

[0102] . According to an alternative embodiment, said band spring 1 comprises a central spring segment 30 with longitudinal extension directed according to the substantially axial direction A-A when the band spring 1 is assembled on said caliper body 11 .

[0103] . According to an alternative embodiment , said fixing portion 10 proj ects with two fixing arms 26, 27 from opposite edges of a first fixing end 31 of said central spring stretch 30 .

[0104] . According to an alternative embodiment , said first fixing end 31 is bent to form a first retaining tooth 34 .

[0105] . According to an alternative embodiment, said action body portion 6 adapted to bias said first brake pad 3 proj ects with two action arms 12 , 13 from opposite edges of an intermediate portion 32 of said central spring segment 30 .

[0106] . According to an alternative embodiment, said reaction body portion 7 adapted to abut against said second brake pad 4 proj ects with two reaction arms 17 , 18 from opposite edges of a second end 33 of said central spring segment 30 , said end being opposite to said first fixing end 31 .

[0107] . According to an alternative embodiment, said second end 33 is bent to form a second retaining tooth 35.

[0108] . According to an alternative embodiment, said band spring 1 comprises a central spring segment 30 with longitudinal extension directed according to the substantially axial direction A-A when the band spring 1 is assembled on said caliper body 11 .

[0109] . According to an alternative embodiment , said fixing portion 10 proj ects with two fixing arms 26, 27 from opposite edges of a first fixing end 31 of said central spring stretch 30 .

[0110] . According to an alternative embodiment, said action body portion 6 adapted to bias said first brake pad 3 proj ects with two action arms 12 , 13 from opposite edges of an intermediate portion 32 of said central spring segment 30 .

[0111] . According to an alternative embodiment, said reaction body portion 7 adapted to abut against said second brake pad 4 proj ects with two reaction arms 17 , 18 from opposite edges of a second end 33 of said central spring segment 30 , said end being opposite to said first fixing end 31 .

[0112] . According to an alternative embodiment , said two reaction arms 17 , 18 each end with a reaction arm reaction segment 19, 20 having an edge portion directed according to a tangent T-T to the circumferential direction C-C and folded to form a third retaining tooth 36.

[0113] . According to an alternative embodiment, said spring body 5 is made in one piece .

[0114] . According to an alternative embodiment, said spring body 5 is made in one piece and is obtained from a single , cut and shaped sheet of spring material .

[0115] . The present invention also relates to a brake caliper 40 comprising a caliper body 11 adapted to be arranged straddling a brake disc 2 .

[0116] . Said brake disc 2 is adapted to rotate about a rotation axis X-X, which defines an axial direction A-A parallel to said rotation axis X-X, a radial direction R-R orthogonal to said rotation axis X-X, and a circumferential direction C-C orthogonal to both said axial direction A-A and said radial direction R-R; and where said radial direction R-R has an outer radial course Re when directed away from said rotation axis X-X and an inner radial course Ri when directed toward said rotation axis X-X .

[0117] . Said brake caliper 40 further comprises a first brake pad3 , or action pad, housed in said caliper body 11 and adapted to be biased against a first braking surface 41 of said brake disc 2 to apply a braking action .

[0118] . Said brake caliper 40 further comprises a second brake pad4 , or reaction pad, housed in said caliper body 11 and adapted to be biased against a second braking surface 42 of said brake disc 2 to apply a braking action .

[0119] . Said brake caliper 40 further comprises at least one band spring 1 as described in any one of the embodiments described above .

[0120] . According to an alternative embodiment , said caliper body 11 is a caliper body of the floating type and comprises a bracket 43 , fixable to a vehicle support , and a floating body 44 which houses thrusting means 45 adapted to bias the first action pad 3 , where said floating body 44 runs along guides 46 supported by saidbracket 43 .

[0121] . According to an alternative embodiment, said floating body 44 comprises a floating body support portion 47 which comprises two opposite caliper body seats 29 which accommodate by snapping the fixing arm ends 28 of the fixing portion 10 of the band spring 1 .

[0122] . The present invention also relates to a disc brake 47 comprising a brake caliper 40 according to any one of the embodiments described above and a brake disc 2 .LIST OF REFERENCE SIGNS1 band spring2 brake disc3 first brake pad or action pad4 second brake pad or reaction pad5 spring body6 action body portion7 reaction body portion8 reaction body portion9 centerline10 fixing portion11 caliper body12 action arm13 action arm14 action segment of action arm15 action segment of action arm16 action arm edge17 reaction arm18 reaction arm19 reaction segment of reaction arm20 reaction segment of reaction arm21 reaction arm end edge22 action surface23 action angle24 reaction surface25 reaction angle26 fixing arm27 fixing arm28 one fixing arm end29 caliper body fixing seat30 central spring segment31 first fixing end of central spring segment32 intermediate portion of central spring segment33 second end of central spring segment34 first retaining tooth of first fixing end35 second retaining tooth of second fixing end36 third retaining tooth40 brake caliper41 first braking surface of brake disc42 second braking surface of brake disc43 bracket44 floating body45 thrusting means46 guides47 disc brakeX-X rotation axis of the brake discA-A axial directionR-R radial directionT-T tangential directionC-C circumferential directionRe outer radial course of the radial directionRi inner radial course of the radial directionPa action planePr reaction plane

Claims

CLAIMS1. A band spring (1) shaped to be arranged straddling a brake disc(2) ; wherein- said brake disc (2) is adapted to rotate about a rotation axis (X- X) , which defines an axial direction (A-A) parallel to said rotation axis (X-X) , a radial direction (R-R) orthogonal to said rotation axis (X-X) , and a circumferential direction (C-C) orthogonal to both said axial direction (A-A) and said radial direction (R-R) ; and wherein said radial direction (R-R) has an outer radial course (Re) when directed away from said rotation axis (X-X) and an inner radial course (Ri) when directed toward said rotation axis (X-X) ;- said band spring (1) being adapted to apply an elastic action to a first brake pad (3) , or action pad, to bias said first brake pad (3) away from said brake disc (2) , thus substantially in the axial direction (A-A) and to bias said first brake pad (3) in the radial direction (R-R) ;- said band spring (1) being adapted to apply an elastic action to a second brake pad (4) , or reaction pad, opposed to said action pad(3) , to bias said second brake pad (4) in the radial direction (R- R) ;- said band spring (1) comprises a spring body (5) ;- said spring body (5) is ribbon-shaped;- said spring body (5) comprises an action body portion (6) adapted to bias said first brake pad (3) ;- said spring body (5) comprises a reaction body portion (7) adaptedto abut against said second brake pad (4) ;- said spring body (5) has a centerline (9) which, when the spring is assembled straddling the brake disc (2) , is a direction tangent to said circumferential direction (C-C) and extending transversely to said axial direction (A-A) and is placed in the middle of said spring body (5) when the extension thereof in the axial direction (A-A) is evaluated;- said spring body (5) has an asymmetric shape with respect to said centerline ( 9) ;- said spring body (5) comprises a fixing portion (10) to fix said band spring (1) to a caliper body (11) , wherein said caliper body (11) is placed straddling said brake disc (2) and accommodates said first and second pads (3, 4) ;- said fixing portion (10) is placed in said action body portion (6) away from said centerline (9) .

2. A band spring (1) according to claim 1, wherein said action body portion (6) comprises two action arms (12, 13) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner; or wherein said action body portion (6) comprises two action arms (12, 13) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner, each with at least one action segment (14, 15) extending in the axial direction (A-A) ;or wherein said action body portion (6) comprises two action arms (12, 13) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner each forming an "L"- shape having at least one action segment (14, 15) extending in the axial direction (A-A) ; or wherein said action body portion (6) comprises two action arms (12, 13) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner, each with at least one action segment (14, 15) extending in the axial direction (A-A) , remaining parallel to each other; or wherein said action body portion (6) comprises two action arms (12, 13) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner, each with at least one action segment (14, 15) having a raised action arm edge (16) .

3. A band spring (1) according to claim 1 or 2, wherein said reaction body portion (7) comprises two reaction arms (17, 18) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner; or wherein said reaction body portion (7) comprises two reaction arms (17, 18) which, when the band spring (1) is disassembled from said caliperbody (11) , project in a cantilevered manner, each with at least one reaction segment (19, 20) extending in a direction tangent to said circumferential direction (C-C) ; or wherein said reaction body portion (7) comprises two reaction arms (17, 18) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner each forming an "S"- shape and with at least one reaction segment (19, 20) extending in a direction tangent to the circumferential direction (C-C) ; or wherein said reaction body portion (7) comprises two reaction arms (17, 18) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner, each with at least one reaction segment (19, 20) extending in a direction tangent to said circumferential direction (C-C) ; or wherein said reaction body portion (7) comprises two reaction arms (17, 18) which, when the band spring (1) is disassembled from said caliper body (11) , project in a cantilevered manner, each with at least one reaction segment (19, 20) having a raised reaction arm end edge(21) .

4. A band spring (1) according to claim 3 when depending on claim 2, wherein said two action arms (12, 13) and said two reaction arms (17, 18) ,when the band spring (1) is disassembled from said caliper body(11) , project in a cantilevered manner separately from one another; or wherein said two action arms (12, 13) and said two reaction arms (17, 18) , when the band spring (1) is disassembled from said caliper body (11) , all four project in a cantilevered manner and separately from one another; or wherein said action arm action segments (14, 15) of said two action arms (12, 13) have greater extension in the axial direction (A-A) than the extension in the axial direction of said reaction arm reaction segments (19, 20) of said two reaction arms (17, 18) .

5. A band spring (1) according to any one of the preceding claims, wherein said action body portion (6) comprises two action arms (12, 13) , wherein when said band spring (1) is disassembled from said caliper body (11) , said two action arms (12, 13) are arranged to form each an action surface (22) placed in an inclined plane or action plane (Pa) which, in a plane comprising the axial (A-A) and radial (R-R) directions, forms an action angle (23) with respect to the axial direction (A-A) ; or wherein said action body portion (6) comprises two action arms (12, 13) , wherein when said band spring (1) is disassembled from said caliperbody (11) , said two action arms (12, 13) are arranged to form each an action surface (22) placed in an inclined plane or action plane (Pa) which, in a plane comprising the axial (A-A) and radial (R-R) directions, forms an action angle (23) with respect to the axial direction (A-A) ; wherein said action angle (23) is of predetermined magnitude so that, when the band spring (1) is assembled in said caliper body (11) and biases said first brake pad (3) , said two action arms (12, 13) are arranged to preload in a predetermined manner the first brake pad (3) to bias said first brake pad (3) in a predetermined and substantially approached manner in the axial direction (A-A) and away from the brake disc (2) and to bias in a predetermined and substantially approached manner the first brake pad (3) in the inner radial direction (Ri) .

6. A band spring (1) according to any one of the preceding claims, wherein said reaction body portion (7) comprises two reaction arms (17, 18) , wherein when said band spring (1) is disassembled from the caliper body (11) , said two reaction arms (17, 18) are arranged to form each a reaction surface (24) placed in an inclined plane or reaction plane (Pr) which, in a plane comprising the circumferential (C-C) and radial (R-R) directions, forms a reaction angle (25) with respect to the direction tangential to the circumferential direction (C-C) ; or whereinsaid reaction body portion (7) comprises two reaction arms (17, 18) , wherein when said band spring (1) is disassembled from the caliper body (11) , said two reaction arms (17, 18) are arranged to form each a reaction surface (24) placed in an inclined plane or reaction plane (Pr) which, in a plane comprising the circumferential (C-C) and radial (R-R) directions, forms a reaction angle (25) with respect to a direction tangential to the circumferential direction (C-C) ; wherein said reaction angle (25) is of predetermined magnitude so that when the band spring (1) is assembled in said caliper body (11) and biases said second brake pad (4) , said two reaction arms (17, 18) are arranged to preload in a predetermined manner the second brake pad (4) to bias said second brake pad (4) in a predetermined and substantially approached manner in the inner radial direction (Ri) .

7. A band spring (1) according to any one of the preceding claims, wherein said fixing portion (10) comprises two fixing arms (26, 27) adapted to snap-couple to the caliper body (11) ; or wherein said fixing portion (10) comprises two fixing arms (26, 27) adapted to snap-couple to the caliper body (11) which extend substantially in the radial direction (R-R) ; or wherein said fixing portion (10) comprises two fixing arms (26, 27) adaptedto snap-couple to the caliper body (11) each with one fixing arm end(28) folded to fit into a fixing seat (29) provided in the caliper body (11) ;8. A band spring (1) according to any one of the preceding claims, wherein said band spring (1) comprises a central spring segment (30) ; and wherein said fixing portion (10) projects from a first fixing end (31) of said central spring segment (30) ; and wherein said action body portion (6) adapted to bias said first brake pad (3) projects from an intermediate portion (32) of said central spring segment (30) ; and wherein said reaction body portion (7) adapted to abut against said second brake pad (4) projects from a second end (33) of said central spring segment (30) , said end being opposite to said first fixing end (31) ; or wherein said band spring (1) comprises a central spring segment (30) with longitudinal extension directed according to the substantially axial direction when band spring (1) is assembled on said caliper body (11) ; and wherein said fixing portion (10) projects with two fixing arms (26, 27) from opposite edges of a first fixing end (31) of said central spring segment (30) ; and wherein said action body portion (6) adapted to bias said first brake pad(3) projects with two action arms (12, 13) from opposite edges of an intermediate portion (32) of said central spring segment (30) ; and wherein the reaction body portion (7) adapted to abut against said second brake pad (4) projects with two reaction arms (17, 18) from opposite edges of a second end (33) of said central spring segment (30) , said end being opposite to said first fixing end (31) ; or wherein said band spring (1) comprises a central spring segment (30) with longitudinal extension directed according to the substantially axial direction when the band spring (1) is assembled on said caliper body (11) ; and wherein said fixing portion (10) projects with two fixing arms (26, 27) from opposite edges of a first fixing end (31) of said central spring segment (30) ; and wherein said first fixing end (31) is folded to form a first retaining tooth (34) ; said action body portion (6) adapted to bias said first brake pad (3) projects with two action arms (12, 13) from opposite edges of an intermediate portion (32) of said central spring segment (30) ; and wherein the reaction body portion (7) adapted to abut against said second brake pad (4) projects with two reaction arms (17, 18) from opposite edges of a second end (33) of said central spring segment (30) , said end being opposite to said first fixing end (31) ; and wherein said second end (33) is folded to form a second retaining tooth (35) ;or wherein said band spring (1) comprises a central spring segment (30) with longitudinal extension directed according to the substantially axial direction when band spring (1) is assembled on said caliper body (11) ; and wherein said fixing portion (10) projects with two fixing arms (26, 27) from opposite edges of a first fixing end (31) of said central spring segment (30) ; and wherein said action body portion (6) adapted to bias said first brake pad (3) projects with two action arms (12, 13) from opposite edges of an intermediate portion (32) of said central spring segment (30) ; and wherein the reaction body portion (7) adapted to abut against said second brake pad (4) projects with two reaction arms (17, 18) from opposite edges of a second end (33) of said central spring segment (30) , said end being opposite to said first fixing end (31) ; and wherein said two reaction arms (17, 18) each end with a reaction arm reaction segment (19, 20) having an edge portion directed according to a tangent to the circumferential direction (C-C) folded to form a third retaining tooth (36) .

9. A band spring (1) according to any one of the preceding claims, wherein said spring body (5) is in one piece; or whereinsaid spring body (5) is in one piece; and is obtained from a single, cut and shaped sheet of spring material.

10. A brake caliper (40) comprising a caliper body (11) adapted to be arranged straddling a brake disc (2) ; wherein- said brake disc (2) is adapted to rotate about a rotation axis (X- X) , which defines an axial direction (A-A) parallel to said rotation axis (X-X) , a radial direction (R-R) orthogonal to said rotation axis (X-X) , and a circumferential direction (C-C) orthogonal to both said axial direction (A-A) and said radial direction (R-R) ; and wherein said radial direction (R-R) has an outer radial course (Re) when directed away from said rotation axis (X-X) and an inner radial course (Ri) when directed toward said rotation axis (X-X) ; said brake caliper (40) further comprises a first brake pad (3) , or action pad, housed in said caliper body (11) and adapted to be biased against a first braking surface (41) of said brake disc (2) to apply a braking action; said brake caliper (40) further comprises a second brake pad (4) , or reaction pad, housed in said caliper body (11) and adapted to be biased against a second braking surface (42) of said brake disc (2) to apply a braking action; said brake caliper (40) further comprises at least one band spring(1) according to any one of the preceding claims.

11. A brake caliper (40) according to claim 10, whereinsaid caliper body (11) is a caliper body of the floating type and comprises a bracket (43) fixable to a vehicle support, and a floating body (44) which houses thrusting means (45) adapted to bias the first action pad (3) , wherein said floating body (44) runs along guides (46) supported by said bracket (43) .

12. A brake caliper (40) according to claim 10 or 11, wherein the floating body (44) comprises a floating body support portion(47) comprising two opposite caliper body seats (29) which accommodate by snapping the fixing arm ends (28) of the fixing portion (10) of the band spring (1) .

13. A brake disc (47) comprising a brake caliper (40) according to any one of claims 10 or 11 and a brake disc (2) .

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